Deeter Wireless Sensor Systems - Get off the Wire and in the Air

May 5, 2011 - PRLog -- The Deeter Wireless Sensor System now makes possible what would have been impossible or impracticable not so long ago. Where it was too expensive to run cabling or where physical barriers were in the way, such as rivers and roads, Deeter wireless radio telemetry now makes remote sensing possible at reasonable cost.

The simplest system consists of a Base Station and a sensor node. There are currently two types of sensor node: an 'LVCS-RF' (Liquid Vertical Continuous Sensor - Radio Frequency), and a general-purpose 'Sender'. The Sender enables remote sensing of:

•up to four switch inputs
•an analogue input
The analogue input can be either a 4-to-20mA current-loop circuit or a resistive input (such as a Deeter LVCS).

The Base Station has the following process control outputs:

•four open-collector transistors
•a 4-to-20mA current-loop driver
The current-loop output responds to the analogue input at the sensor node. The transistor outputs can either reflect the state of the switch inputs or they can be configured to turn on and off at analogue input set points.

The system communicates using the IEEE 802.15.4 wireless network protocol, in the internationally approved, licence-free, 2.4GHz frequency band. Wireless range can be up to 1km, subject to environmental conditions, antennae location and interference from other radio equipment. For greater range, or where the link quality is not sufficient, up to four Deeter Wireless Routers can be added to the system.

The Base Station is at the heart of the Deeter Wireless Sensor System, designed to communicate with a Deeter Sender or LVCS-RF and convert remote sensor input signals into useful outputs.

The Base Station acts as the coordinator for a wireless network. It operates on one of 16 radio frequency channels available in the 2.4GHz ISM band. Range can be more than 1km, subject to environmental factors, and greater distances can be attained with the use of a Deeter Wireless Router.

The internationally recognised IEEE 802.15.4 protocol allows several networks to share the same space without interfering with each other.

The Base Station provides the following process outputs:

•Four Open-collector transistor outputs. These may be used to drive external relays (for example a Deeter Dual Level Controller) for pumps and alarms. The outputs will sink up to 50mA at 40V and are short-circuit protected.
•A 4-to-20mA current-loop driver. This allows interfacing with industrial process controllers or the range of Deeter Current Loop Indicators.
•A serial communications channel provides full-duplex RS232 and half-duplex RS485 transceivers. This allows software to be developed for linking to PCs, dataloggers, PLCs and so forth (Future feature). A USB connection is also available.
The Base Station has three internal push-button switches and a 2-line by 16-character LCD. The buttons are accessible with the lid removed and are used in conjunction with the display to select installation options during initial setup. Once the system has been installed it will continue to operate without any need for user intervention.

The Base Station is housed in a rugged ABS enclosure with an external antenna. It has cable glands for power input and signal outputs.

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The Deeter Group is regarded as a leading international company in the design, development and production of electronic sensors, switches and control and instrumentation systems.